While the Joker’s sage words may hold true for a joke, the opposite is more accurate for a film, and “The Killing Joke” won’t reach the classic status of its graphic novel inspiration because it’s simply not that good.

To be fair, the feature-length, R-rated film does just fine when it sticks to the source material. (The above line is a new addition.) But an attempt in the introduction to better paint Barbara Gordon’s motivations — a necessary, if ill-plotted expansion for the sake of time — ends up making the victim even more disposable than before.

Opening with Barbara as Batgirl, the film lends her the narrative voice of authority. We watch as she struggles to come to terms with her diminished role next to Batman; a dynamic that becomes more and more complicated as the two investigate a young, violent mob boss attempting to takeover the family business from his father. As the threat level increases for Batgirl, Batman pushes her further and further away.

While he attempts to justify his lack of faith by citing her inexperience — she’s in it for the thrill, while he’s doing it for a purpose — Batman’s judgment is called into question when the “partners'” relationship turns…romantic? Well, maybe it’s not romantic, considering Bruce and Barbara don’t exactly swap gifts or sit down for a candlelight dinner, but the two are nonetheless sexualized in an attempt to further humanize Barbara — a character readers know will soon become the victim.

“The Killing Joke”

Warner Bros.

On the one hand, it’s easy to imagine why screenwriter Brian Azzarello and director Sam Liu would make this choice, even beyond the practical demand of extending “The Killing Joke” to feature length. Barbara isn’t much more than a prop in the original graphic novel; a prop that gets sexually exploited and thus becomes a motivating factor for her father, who becomes a means to justify whatever Batman decides to do in a brilliantly ambiguous ending. Filling out her role could have created a direct attachment between Barbara and Batman, but instead of humanizing her, it turns Barbara/Batgirl into a comic book cliche: The female character that feigns complexity, but, when given an expanded role, is only viewed through a sexual lens.

Making matters worse is how the relationship affects Batman. Despite the graphic novel cutting to the heart of our hero’s moral quandaries, the movie paints him as an emotionally-deadened jerk. Not only does he give into his baser instincts in an obviously inappropriate fashion, but the film never explains how and why he did it. Nor do they allow Batman to try to make it right or even openly discuss his sins with those he hurts. It makes his resolute demeanor in regard to saving the Joker all the more baffling, as he’s too good to kill a criminal who’s asking for it, but he’s not strong enough to pick up the phone when his lady friend is calling.

Supporters may argue the themes are what matters, and “Batman: The Killing Joke” does hold true to most of the topics introduced in the graphic novel. But the confounding additions muddle the overall message, not quite making Batman into the “ordinary” man pushed to the limits by an extraordinary evil, nor is Batgirl the new example of virtuosity. They’re flawed, yes, but in a manner too disconnected from the graphic novel’s central conflict.

Making things all the more instinctually complicated is the medium itself. Super-fans are ecstatic the voices of Batman and the Joker — in everything from “Batman: The Animated Series” to “Batman: Mask of the Phantasm” (the only animated Batman to earn a theatrical release until this one) — have returned, along with animation harkening back to the fan favorites from the early ’90s. But hearing Hamill’s voice — who is still the best Joker of all time, animated or otherwise — coming from a character this depraved, this violent and this sexualized is bound to be jarring for anyone who grew up with a Joker who “put the fun in funeral” on “BTAS.” At least Kevin Conroy alters Batman’s voice for the new iteration, creating a separation between his previous work and this R-rated offering. Hamill embraces a character he perfected long ago, even if it may have helped to hear him as we see him — differently.

While it may seem instinctual to want an R-rated “Batman,” especially from a graphic novel that would deserve the rating without alterations, “Batman: The Killing Joke” is borderline unsettling — and not in a good way. While the source material is preserved with reverence to key artistry from Brian Bolland, the overall film gets lost between Batman, the bad boyfriend, the Joker, an evil unseen in animation, and where, exactly, Barbara is supposed to fit into all this.